1. Field of the Invention
The present invention relates to an intravascular catheter assembly and more particularly to an improved intravascular catheter assembly which provides for fluid connection with various types of fluid conducting devices and which includes a safety sheath that houses a retractable needle and a backflow device that includes an improved self-closing valve member.
2. Description of Related Art
In conventional practice, an intravascular catheter is introduced into a vein of a person by using a sharp hollow bore needle within the bore of the catheter. The hollow bore needle acts as a sharp introducing instrument over which the catheter may be advanced into the vein of the patient. When the needle is inserted, blood flows back through the needle, usually into a small collection container for the blood. When the introducing needle is withdrawn from the catheter and the catheter is moved further into the patient's vein, excessive bleeding and other fluid leakage often occurs during the period of time before the catheter is connected to other equipment which controls the backflow of blood into the catheter. Also, the introducing needle must be quickly and safely disposed of. A common practice during this period between withdrawal of the needle used to introduce the catheter into the vein and connection of the catheter to equipment having a blood flow control device is for the operator to palpate the vein into which the catheter is introduced at the skin's surface immediately ahead of the catheter tip. During palpatation of the vein, the operator compresses the vein into which the catheter has been introduced to prevent or reduce blood flow. However, this procedure is inconvenient in that it necessitates either multiple operators or a single operator who must manipulate with only one hand both the safe withdrawal and disposal of the needle, as well as the connection of the catheter to equipment with fluid control devices. This may be especially difficult when a combative patient is being transported in an ambulance or other emergency vehicle and an intravenous (I.V.) drip set must be started to control the patient's condition. If the patient struggles and the I.V. set comes loose from the catheter, excessive bleeding from the catheter results which can frighten the patient and intensify psychological fear, pain, and emotion.
Very dangerous situations may also arise when a conventional catheter is used on a diseased person who has hepatitis, meningitis, or AIDS or other diseases transmitted by blood. When the sharp, elongated needle used to introduce the catheter into the patient's vein is withdrawn and the catheter is moved further into the vein, the bleeding and fluid leakage from the catheter may expose the operator to contact the patient's blood thus resulting in the possible transmission of the disease carried by the patient to the personnel attending the patient. Further, if the introducing needle is not safely and quickly disposed of, the needle itself may be accidently caused to prick the operator or other personnel involved in disposing of used equipment, such as the needle.
Various attempts have been made to incorporate fluid control devices into catheters in order to control the fluid loss from the catheter. These devices include sealing members made of elastomeric material having a perforation formed therein which re-seals because of the structural confinement of the elastic material and are disclosed, for example, in U.S. Pat. Nos. 3,853,127; 4,177,814; and 4,626,245. Attempts have also been made at providing a means for shielding a needle used in venipuncture as disclosed in U.S. Pat. Nos. 3,595,230; 4,676,783; 4,747,831; and 4,643,199. These conventional devices have not solved all of the problems described above and often are expensive and cumbersome to manufacture. Therefore, there is a need for an improved intravascular catheter assembly having an improved backflow device and an improved needle sheath which solves the above-noted problems and which has a simplified structure so as to be advantageous for manufacture.